Is this really a Major Update?
Well, you see, it went from 5.2.9 to 5.3.0 so that seems pretty major. But in reality, I just want some attention.
The update is pretty simple actually, vendors on the Mothership Altair will now restock some items with each visit. Previously they would only restock when you completed a part of the main quest.
Now every time you visit, they have a random chance of restocking any empty item slots, up to the first seven or so. The likelyhood of restocking is tied to the difficulty level on which you are playing. Easier modes will have a higher likelyhood of restocking than harder modes.